New polymeric biomaterials-phospholipid polymers with a biocompatible surface.

New biomedical polymers were designed with attention to the surface of biological membranes, i.e. the surface was completely covered with phospholipid polar groups. The polymers with a phosphorylcholine group, 2-methacryloyloxyethyl phosphorylcholine (MPC) co-polymerized with hydrophobic alkyl group, could interact with phospholipids in plasma selectively and strongly. The adsorbed phospholipids on the polymer surface were concentrated, organized each other and then formed a self-assembled biomimetic membrane surface. The surface showed excellent resistance for both protein adsorption and blood cell adhesion, i.e. the MPC polymer showed good blood compatibility. Based on these characteristics of the MPC polymer, it was applied to improve the biocompatibility and biostability of an implantable glucose sensor. The relative output current of the sensor covered with the MPC polymer membrane was maintained as the initial level even after 14 days of subcutaneous implantation in a rat. Therefore, it is concluded that the MPC polymer membrane is an excellent material for implantable biomedical devices.